<div class="input-box">
  <label class="input-label">Email</label>
  <input placeholder="user@mail.com" class="input" name="email" type="email">
  <span class="input-helper">enter a valid email</span>
</div>
<style>
/* From Uiverse.io by rricol - Tags: email, input */
.input {
  position: relative;
  max-width: 190px;
  border: none;
  box-shadow: 0px 1.5px 0px 0px #858585;
  padding: .5rem;
  transition: all 200ms ease-in-out;
  opacity: .8;
}

.input-box {
  display: flex;
  flex-direction: column;
}

.input-label {
  font-size: .625rem;
  font-weight: bold;
  color: #858585;
  margin-bottom: 4px;
  margin-left: 1px;
}

.input-helper {
  color: #858585;
  font-size: .5rem;
  margin-top: 6px;
  margin-left: 1px;
  visibility: hidden;
  transform: translateY(-.5rem);
  transition: all 100ms linear;
  z-index: -1;
}

.input::placeholder {
  color: rgb(145, 145, 145);
  font-size: .75rem;
}

.input::after {
  content: attr(placeholder);
  position: absolute;
  color: #161616;
  top: 0;
  left: 0;
}

.input:focus {
  border: none;
  box-shadow: 0px 1.5px 0px 0px #72E985;
  outline: none;
}

.input:focus + .input-helper {
  visibility: visible;
  transform: translateY(0rem);
}

.input:focus::placeholder {
  visibility: hidden;
}
</style>
